690 MESSRS. BRADY AND ROBERTSON ON [Nov. 21, 



It will be observed that though the two birds are nearly the same 

 in linear dimensions, A. ncevioides is a heavier and more robust bird ; 

 its beak is larger and more massive, and its tarsi, toes, and claws are 

 longer. 



3. Descriptions of two new Species of British Holothuroidea. 

 By George Stewardson Brady, C.M.Z.S., and David 

 Robertson, F.G.S. 



[Eeceived October 27, 1871.] 

 (Plates LXXI. & LXXII.) 



Synapta tenera, Norman. (Plate LXXI. figs. 1-4.) 



Body about eight times as long as broad, tapering slightly towards 

 the posterior extremity : tentacles short and sparingly pinnate. 

 Anchor-plates few in number, subpentagonal, with a broad handle 

 or pedicle, the length of which is equal to about one half the width 

 of the plate : one broadly ovate, crenulated, central perforation, sur- 

 rounded by five of similar size and sbape and another crescenti- 

 form, the last named being situate just above the base of the pedicle. 

 The pedicle itself has near its base a wedge-shaped aperture, and at 

 the free extremity two or three irregular sublinear perforations. The 

 anchors themselves are slightly longer than the anchor-plates, and 

 are often minutely and irregularly perforated in the shaft and arms. 

 At the bases of the tentacles are a few minute spicules, curvilinear 

 in form, with divaricated furcate extremities (fig. 4). The whole 

 animal is very tender and delicate in structure, and almost perfectly 

 transparent, five opaque white longitudinal lines, however, being 

 very conspicuous. Length an inch to an inch and a half. 



The only locality in which we have met with this species is the 

 Frith of Clyde, where it occurs not unfrequently in black ooze, in 

 a depth of 15-30 fathoms. 



Synapta tenera was named and briefly referred to by the Rev. 

 A. M. Norman at a meeting of the British Association some few 

 years ago, his remarks being based upon specimens taken by Mr. 

 Robertson in the above-mentioned locality. 



Cucumaria saxicola, uov. sp. (Plate LXXII.) 



Body of nearly equal thickness throughout, scarcely at all tapering 

 at the extremities ; skin excessively thick and strong. The spicules 

 of the body are usually subrhomboidal in shape (fig. 3 a), but in pro- 

 cess of growth tend to lengthen out at the extremities (fig. 3 b); 

 each plate has in the centre four oval perforations arranged diamond- 

 wise, the two in the short axis being the largest ; but as the plate 

 increases in size more perforations become developed in the direction 

 of the long axis (b). These plates are by no means very thickly set, 

 and are interspersed with numerous much smaller spicules of a stel- 



